html php 第一次加载页面

if ($_REQUEST['Submit']=='增加')
{
$sql="INSERT INTO role_privileges VALUES ('$user_id','$priv_id')";
$result = mysql_query($sql);
printf ("role_id: %s priv_id: %s",$user_id, $priv_id);
}
if ($_REQUEST['Submit']=='删除')
{
$sql="delete from role_privileges where role_id = ".$user_id;
$result = mysql_query($sql);
printf ("role_id: %s ",$user_id);
}
if ($_REQUEST['Submit']=='加一')
{
//$sql="delete from role_privileges where role_id = ".$user_id;
//$result = mysql_query($sql);
//printf ("role_id: %s ",$user_id);
$temp=$temp+1;
echo $temp."kddddddddddddddddd";
}

echo "<br>";
echo "操作 ". $_REQUEST['Submit'];

echo "<br>";
echo "<br>";
echo "<br>";
echo "全部数据";
echo "<br>";
$sql="select * from role_privileges";
$result = mysql_query($sql);
?>

<table border='0' cellpadding='0' cellspacing='1' class="tab">
<tr bgcolor="#f87820" align="center">

<td class="tabhead" width="90">role_id</td>
<td class="tabhead" width="90">priv_id</td>
</tr>
<?
while ($row = mysql_fetch_array($result, MYSQL_NUM))//显示的关键
{
//printf ("role_id: %s priv_id: %s", $row[0], $row[1]);
//echo "<br>";
echo "<tr align=center >";
echo "<td class='tabval'>";
echo $row[0];
echo "</td>";
echo "<td class='tabval'>";
echo $row[1];
echo "</td>";
echo "</tr>";
}

?>
</table>
<form id="form1" name="form1" method="post" action="user.php">
<br>
<br>
<br>        
<label><span class="inputsub">用户ID</span>
<input type="text" name="textfield" />
</label>
<label >权限代码
<input type="text" name="textfield2" />
</label>
<br>
<br>
<br>
<br>        
<label><span class="inputsub">
<input type="submit" name="Submit" value="查询" /></span>
</label>
 
<label>
<input type="submit" name="Submit" value="更新" />
</label>
 
<label>
<input type="submit" name="Submit" value="增加" />
</label>
 
<label>
<input type="submit" name="Submit" value="删除" >
</label>
<label>
<input type="submit" name="Submit" value="加一" >
</label>
</form>
<p class="inputsub"><?php echo trim(date("Y-m-d H:i:s"));?></p>
</body>
</html>
这一大段代码，PHP 跟据表单传过来的内容来判断是执行那一个操作，现在问题出来了，每点一下，整个代码都跑了一次，这好像不太合理，有什么好办法可以解决这个问题，比如说函数，在网页由于问题没有描述清楚找不到相关的问题。